Door mail slot soundproofing possible?

Hi all,

Exploring some front door soundproofing options here. Was wondering... could front door mail slot be soundproofed (well) at all? Perhaps there are products, mail slots that is, out there specially designed with soundproofing in mind. If anybody is aware of such a product I'd appreciate your feedback.

Yeah, it's a hole and the best soundproofing is not having it there. I thought I'd ask if there is some sort of "special" mail slot out there with adequate soundproofing qualities, before considering filling that in and adding a mail box on the side.